Make seriesToPoints_ and stackPoints_ private. They are being rendered as part of...

[dygraphs.git] / dygraph-canvas.js

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index 90ef027..cba4f44 100644 (file)
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -39,8 +39,8 @@
  * The chart canvas has already been created by the Dygraph object. The
  * renderer simply gets a drawing context.
  *
- * @param {Dyraph} dygraph The chart to which this renderer belongs.
- * @param {Canvas} element The <canvas> DOM element on which to draw.
+ * @param {Dygraph} dygraph The chart to which this renderer belongs.
+ * @param {HTMLCanvasElement} element The <canvas> DOM element on which to draw.
  * @param {CanvasRenderingContext2D} elementContext The drawing context.
  * @param {DygraphLayout} layout The chart's DygraphLayout object.
  *
@@ -58,6 +58,7 @@ var DygraphCanvasRenderer = function(dygraph, element, elementContext, layout) {
   this.width = this.element.width;
 
   // --- check whether everything is ok before we return
+  // NOTE(konigsberg): isIE is never defined in this object. Bug of some sort.
   if (!this.isIE && !(DygraphCanvasRenderer.isSupported(this.element)))
       throw "Canvas is not supported.";
 
@@ -433,14 +434,16 @@ DygraphCanvasRenderer.prototype._updatePoints = function() {
 
 /**
  * Add canvas Actually draw the lines chart, including error bars.
- * If opt_seriesName is specified, only that series will be drawn.
- * (This is used for expedited redrawing with highlightSeriesOpts)
- * Lines are typically drawn in the non-interactive dygraph canvas. If opt_ctx
- * is specified, they can be drawn elsewhere.
  *
  * This function can only be called if DygraphLayout's points array has been
  * updated with canvas{x,y} attributes, i.e. by
  * DygraphCanvasRenderer._updatePoints.
+ *
+ * @param {string=} opt_seriesName when specified, only that series will
+ *     be drawn. (This is used for expedited redrawing with highlightSeriesOpts)
+ * @param {CanvasRenderingContext2D} opt_ctx when specified, the drawing
+ *     context.  However, lines are typically drawn on the object's
+ *     elementContext.
  * @private
  */
 DygraphCanvasRenderer.prototype._renderLineChart = function(opt_seriesName, opt_ctx) {
@@ -699,7 +702,14 @@ DygraphCanvasRenderer._fillPlotter = function(e) {
   var stackedGraph = g.getOption("stackedGraph");
   var colors = g.getColors();
 
-  var baseline = {};  // for stacked graphs: baseline for filling
+  // For stacked graphs, track the baseline for filling.
+  //
+  // The filled areas below graph lines are trapezoids with two
+  // vertical edges. The top edge is the line segment being drawn, and
+  // the baseline is the bottom edge. Each baseline corresponds to the
+  // top line segment from the previous stacked line. In the case of
+  // step plots, the trapezoids are rectangles.
+  var baseline = {};
   var currBaseline;
   var prevStepPlot;  // for different line drawing modes (line/step) per series
 
@@ -736,6 +746,9 @@ DygraphCanvasRenderer._fillPlotter = function(e) {
       var point = iter.next();
       if (!Dygraph.isOK(point.y)) {
         prevX = NaN;
+        if (point.y_stacked !== null && !isNaN(point.y_stacked)) {
+          baseline[point.canvasx] = area.h * point.y_stacked + area.y;
+        }
         continue;
       }
       if (stackedGraph) {